Andy Friesen wrote:

>> a. if (a is not null)
>> b. if (a not is null)
>> c. if not (a is null) etc.
>>
>> isnot has less potential for confusion.
> 
> 
> I highly doubt this would be an issue.  Almost everybody is going to do the most obvious that comes to mind: write it out like plain old English.
> 
> Unless like Yoda they talk, correct will they be!

Unless with Visual Basic they code:
  If Not X Is Nothing Then
  If Not IsNull(X) Then

James McComb

Kris wrote:

> Know wot' u mean guv', but "is not" seems a tad verbose, whereas:
> 
> if (x not null)
> 
> sounds fine to me (D "is not" COBOL :~)
> 
> However, I think the best suggestion was put forward by Ben:
> 
> if (x AINT null)

That's pure genius :)


Sean

James McComb wrote:

> a. if (a is not null)
> b. if (a not is null)
> c. if not (a is null) etc.
> 
> isnot has less potential for confusion.

One of the most important python goal is readability...

Python 2.3.4 (#53, May 25 2004, 21:17:02) [MSC v.1200 32 bit (Intel)] on win32
Type "help", "copyright", "credits" or "license" for more information.
>>> a = 1
>>> a is not None
True
>>> a not is None
  File "<stdin>", line 1
    a not is None
           ^
SyntaxError: invalid syntax
>>> not (a is None)
True
>>>

---
Paolo Invernizzi

I agree that "is not" is the most desirable form. I don't think anyone would (seriously) disagree with that. But D is specifically designed to be easy to implement, so I am prepared to go for "isnot" if that makes it acceptable to Walter.




"Paolo Invernizzi" <arathorn@NOSPAM_fastwebnet.it> wrote in message news:cdqcds$1j3c$1@digitaldaemon.com...
> James McComb wrote:
>
> > a. if (a is not null)
> > b. if (a not is null)
> > c. if not (a is null) etc.
> >
> > isnot has less potential for confusion.
>
> One of the most important python goal is readability...
>
> Python 2.3.4 (#53, May 25 2004, 21:17:02) [MSC v.1200 32 bit (Intel)] on
> win32
> Type "help", "copyright", "credits" or "license" for more information.
>  >>> a = 1
>  >>> a is not None
> True
>  >>> a not is None
>    File "<stdin>", line 1
>      a not is None
>             ^
> SyntaxError: invalid syntax
>  >>> not (a is None)
> True
>  >>>
>
> ---
> Paolo Invernizzi

"Matthew" <admin.hat@stlsoft.dot.org> wrote in message news:cdqeaj$1kjh$1@digitaldaemon.com...
> I agree that "is not" is the most desirable form. I don't think anyone
would (seriously) disagree with that. But D is
> specifically designed to be easy to implement, so I am prepared to go for
"isnot" if that makes it acceptable to Walter.

What? You don't think Walter would go for "aint" ?
D would enter the halls of notoriety overnight!

:-)

I agree that !(a is b) is cumbersome.

"is not" would be better. Or maybe something more similar to the normal D syntax?

What about a !is b ?


Matthew wrote:
> While I like the use of is - for one thing, I can reorder the expression to read more naturally, i.e. "hkey is null"
> rather than "null === hkey" - I don't like the need to ! the expression.
> 
> Presumably the reason for preferring "is" over "===" is that it reads better, which it does in the === case.
> 
>     "hkey is null"
> 
> is better than
> 
>     "hkey === null"
> 
> But it seems a starkyl retrograde step to have write "!(hkey is null)" instead of "hkey !== null"
> 
>     "hkey !== null"
> 
> is (much!) better than
> 
>     "!(hkey is null)"
> 
> So, if "!(hkey is null)" is not to people's tastes, as I suggest is the case, then we might end up with an inconsistent
> use of "is" for null, and "!==" for not null. That is not good.
> 
> I suggest that, either:
> 
> (i) we have the keyword modifier "not", as in "hkey is not null", or have an isnot keyword, as in "hkey isnot null", or
> 
> (ii) forget about is for testing null-ness.
> 
> Thoughts?
> 
> 
> 
> 

Leading on from that Hauke, what about this:

if (a ! b)

A bit terse perhaps? Maybe conflicts with a template identifier? Might cause issues where an '=' was not typed by mistake?

Regardless; is this notion another candidate for an operator overload?


"Hauke Duden" <H.NS.Duden@gmx.net> wrote in message news:cdqhnh$1m2l$1@digitaldaemon.com...
> I agree that !(a is b) is cumbersome.
>
> "is not" would be better. Or maybe something more similar to the normal D syntax?
>
> What about a !is b ?
>
>
> Matthew wrote:
> > While I like the use of is - for one thing, I can reorder the expression
to read more naturally, i.e. "hkey is null"
> > rather than "null === hkey" - I don't like the need to ! the expression.
> >
> > Presumably the reason for preferring "is" over "===" is that it reads
better, which it does in the === case.
> >
> >     "hkey is null"
> >
> > is better than
> >
> >     "hkey === null"
> >
> > But it seems a starkyl retrograde step to have write "!(hkey is null)"
instead of "hkey !== null"
> >
> >     "hkey !== null"
> >
> > is (much!) better than
> >
> >     "!(hkey is null)"
> >
> > So, if "!(hkey is null)" is not to people's tastes, as I suggest is the
case, then we might end up with an inconsistent
> > use of "is" for null, and "!==" for not null. That is not good.
> >
> > I suggest that, either:
> >
> > (i) we have the keyword modifier "not", as in "hkey is not null", or
have an isnot keyword, as in "hkey isnot null", or
> >
> > (ii) forget about is for testing null-ness.
> >
> > Thoughts?
> >
> >
> >
> >

"Hauke Duden" <H.NS.Duden@gmx.net> wrote in message news:cdqhnh$1m2l$1@digitaldaemon.com...
> I agree that !(a is b) is cumbersome.
>
> "is not" would be better. Or maybe something more similar to the normal D syntax?
>
> What about a !is b ?

It's a mix of a word and an operator. I think one or the other is best. Just my opinion

>
>
> Matthew wrote:
> > While I like the use of is - for one thing, I can reorder the expression to read more naturally, i.e. "hkey is null" rather than "null === hkey" - I don't like the need to ! the expression.
> >
> > Presumably the reason for preferring "is" over "===" is that it reads better, which it does in the === case.
> >
> >     "hkey is null"
> >
> > is better than
> >
> >     "hkey === null"
> >
> > But it seems a starkyl retrograde step to have write "!(hkey is null)" instead of "hkey !== null"
> >
> >     "hkey !== null"
> >
> > is (much!) better than
> >
> >     "!(hkey is null)"
> >
> > So, if "!(hkey is null)" is not to people's tastes, as I suggest is the case, then we might end up with an
inconsistent
> > use of "is" for null, and "!==" for not null. That is not good.
> >
> > I suggest that, either:
> >
> > (i) we have the keyword modifier "not", as in "hkey is not null", or have an isnot keyword, as in "hkey isnot null",
or
> >
> > (ii) forget about is for testing null-ness.
> >
> > Thoughts?
> >
> >
> >
> >

"Kris" <someidiot@earthlink.dot.dot.dot.net> wrote in message news:cdqifu$1mcn$1@digitaldaemon.com...
> Leading on from that Hauke, what about this:
>
> if (a ! b)

Not obvious enough, sorry

> A bit terse perhaps? Maybe conflicts with a template identifier? Might cause issues where an '=' was not typed by mistake?
>
> Regardless; is this notion another candidate for an operator overload?

No

> "Hauke Duden" <H.NS.Duden@gmx.net> wrote in message news:cdqhnh$1m2l$1@digitaldaemon.com...
> > I agree that !(a is b) is cumbersome.
> >
> > "is not" would be better. Or maybe something more similar to the normal D syntax?
> >
> > What about a !is b ?
> >
> >
> > Matthew wrote:
> > > While I like the use of is - for one thing, I can reorder the expression
> to read more naturally, i.e. "hkey is null"
> > > rather than "null === hkey" - I don't like the need to ! the expression.
> > >
> > > Presumably the reason for preferring "is" over "===" is that it reads
> better, which it does in the === case.
> > >
> > >     "hkey is null"
> > >
> > > is better than
> > >
> > >     "hkey === null"
> > >
> > > But it seems a starkyl retrograde step to have write "!(hkey is null)"
> instead of "hkey !== null"
> > >
> > >     "hkey !== null"
> > >
> > > is (much!) better than
> > >
> > >     "!(hkey is null)"
> > >
> > > So, if "!(hkey is null)" is not to people's tastes, as I suggest is the
> case, then we might end up with an inconsistent
> > > use of "is" for null, and "!==" for not null. That is not good.
> > >
> > > I suggest that, either:
> > >
> > > (i) we have the keyword modifier "not", as in "hkey is not null", or
> have an isnot keyword, as in "hkey isnot null", or
> > >
> > > (ii) forget about is for testing null-ness.
> > >
> > > Thoughts?
> > >
> > >
> > >
> > >
>
>

Hauke Duden schrieb:

> I agree that !(a is b) is cumbersome.
> 
> "is not" would be better. Or maybe something more similar to the normal D syntax?
> 
> What about a !is b ?

I'd vote for !is!